It's 2018 and displacement CC should have actual counters

I'm not gonna lie, everytime I play a melee/tanky champion, I see myself buying Tabi instead of Mercs about 90% of the time. The only exception literally is when the enemy team has tons of CC that isn't displacement/knock-ups or has no physical damage/auto-attackers (which sometimes happens in ARAM since I mostly play that mode but it will usually not occur on Summoner's Rift). With the champion pool becoming bigger and bigger over the years, knock-ups and other displacement spells became more and more prevalent. Crowd Control being so difficult to counter is one of the main contributors to why non-Tank melee classes have the tendency to become close to useless in teamfights. Not many champions buy Mercs simply because Tenacity is an outdated stat and there's only one way to fix that: the stat should be outright reworked. Firstly, a simple short-time fix would be to make it work against knock-ups at least, this should be fairly easy to implement. But for a long term solution, the aim should be to create a stat able to counter other forms of displacement CC as well. Knock-backs ect. are one of the few game elements that just don't have any direct counter in the form of an item and I think that's a big problem.